title: Paracrine control of steroid hormone secretion by chromaffin cells in the adrenal gland of lower vertebrates.
abstract: The adrenal glands of lower vertebrates display a notable intermingling between steroidogenic and chromaffin tissues, which increases from Pisces to Aves. As in mammals, adrenal chromaffin cells contain and release, in addition to catecholamines, serotonin and several peptides, which may affect the secretory activity of steroidogenic cells in a paracrine manner. Stimulatory molecules include serotonin, arginine-vasotocin, tachykinins, vasoactive intestinal peptide, pituitary adenylate cyclase-activating peptide and calcitonin gene-related peptide; inhibitory molecules are dopamine, somatotropic hormone-release inhibiting hormone and galanin. Epinephrine and norepinephrine appear to stimulate steroid secretion in Aves and to inhibit it in Pisces, while their action in Amphibia is controversial. Likewise, atrial natriuretic peptide exerts an anti-secretagogue action in Amphibia and a marked secretagogue effect in Pisces and Aves. The effects of opioids (enkephalins and endorphins) have scarcely been investigated and the findings obtained are highly questionable. Compared with the amazing mass of investigations carried out in mammals, studies in lower vertebrates are few, and in large part performed in Amphibia and Aves. It appears that much further work has to be done by comparative endocrinologists to fully clarify the physiological relevance of the functional interactions between chromaffin and steroidogenic cells in the adrenal glands of lower vertebrates.
authors.affiliation: Department of Anatomy, University of Padua, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Mazzocchi
authors.forename: G
authors.initials: G
authors.lastname: Gottardo
authors.forename: G G
authors.initials: GG
authors.lastname: Nussdorfer
mesh_terms: D000302:Adrenal Cortex / Q000166:cytology / Q000378:metabolism*; D000313:Adrenal Medulla / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D002395:Catecholamines / Q000378:metabolism; D019439:Chromaffin Cells / Q000378:metabolism*; D006801:Humans; D019899:Paracrine Communication / Q000502:physiology*; D012701:Serotonin / Q000378:metabolism; D013256:Steroids / Q000378:metabolism*
chemical_list: D002395:Catecholamines; D013256:Steroids; D012701:Serotonin